Re: [PATCH v2] kbuild, LLVMLinux: Supress warnings unless W=1-3

[Michal Marek <mmarek@suse.cz>]

Dne 31.7.2014 18:12, Behan Webster napsal(a):
> On 07/31/14 01:18, Michal Marek wrote:
>> Dne 31.7.2014 06:16, behanw@converseincode.com napsal(a):
>>> @@ -55,6 +45,18 @@ warning-3 += -Wswitch-default
>>>   warning-3 += $(call cc-option, -Wpacked-bitfield-compat)
>>>   warning-3 += $(call cc-option, -Wvla)
>>>   +ifeq ($(COMPILER),clang)
>>> +ifndef $(W)
>>> +KBUILD_CFLAGS += $(call cc-disable-warning, initializer-overrides)
>>> +KBUILD_CFLAGS += $(call cc-disable-warning, unused-value)
>>> +KBUILD_CFLAGS += $(call cc-disable-warning, format)
>>> +KBUILD_CFLAGS += $(call cc-disable-warning, unknown-warning-option)
>>> +KBUILD_CFLAGS += $(call cc-disable-warning, sign-compare)
>>> +KBUILD_CFLAGS += $(call cc-disable-warning, format-zero-length)
>>> +KBUILD_CFLAGS += $(call cc-disable-warning, uninitialized)
>>> +endif
>>> +endif
>>> +
>> Please remove this part, it has no effect. I assume that if it works for
>> you, these warning are not as annoying so they do not need to be
>> disabled?
> Actually they are annoying, that's why they're disabled normally. Most
> of them complain about practices which are relatively common in kernel
> code.
> 
> clang warns about a lot more things than gcc does. It means that code
> which compiles cleanly in gcc often doesn't with clang. This cuts out
> the warnings which are unlikely to to be fixed in kernel code anytime
> soon, but which are probably worth exposing when W=1 is used.
> 
> This part of the patch explicitly deals with complaints from some in the
> kernel community that clang is too noisy with kernel code.
> 
> This part of the patch needs to be somewhere. This seemed the best place.

You placed it inside a branch that is only evaluated when W= is given.

Michal